(USA TODAY) -- The Senate voted 63-34 to approve President Obama's nomination of John Brennan to lead the CIA Thursday afternoon, ending a week of debate that featured one of the longest filibusters in Senate history.

Brennan, Obama's counterterrorism adviser and a 25-year CIA veteran, takes over an agency supervising a series of controversial drone strikes against terrorism suspects in Afghanistan, Pakistan and around the world.

Those airstrikes, which have exacted a toll on al-Qaeda and the Taliban, were the subject of the 13-hour filibuster Wednesday by Sen. Rand Paul, R-Ky., who questioned the constitutionality of drone strikes without legal due process.

Brennan's confirmation immediately followed an 81-16 vote to end debate on the nomination, which had been delayed by Paul's filibuster and other requests for more documents about the airstrikes from the White House and Justice Department.

On Thursday morning, Senate Majority Leader Harry Reid, D-Nev., said the Brennan votes were scheduled for Saturday unless lawmakers agreed to vote earlier. The final votes were moved up to Thursday afternoon after Attorney General Eric Holder wrote Paul to tell him that Obama would not authorize drone strikes in the United States without court approval.

White House spokesman Jay Carney said Holder's letter to Paul answered the senator's question about whether drones could be used against U.S. citizens on American soil. Carney, quoting from the letter, said: "Does the president have the authority to use a weaponized drone to kill an American not engaged in combat on American soil? The answer is no."

Carney said White House officials have also been in touch with Paul's office.

Obama praised Brennan in a statement after the vote, saying the confirmation showed the Senate has "recognized in John the qualities I value so much-his determination to keep America safe, his commitment to working with Congress, his ability to build relationships with foreign partners, and his fidelity to the values that define us as a nation."

Before debate was ended, two of the Senate's Republican leaders on national security policy assailed Paul and his filibuster allies, calling their rhetoric alarmist and politically motivated.

Sen. John McCain of Arizona, the 2008 Republican nominee for president, said Paul and other Republicans who participated in the filibuster did a disservice by making Americans "think that somehow they're in danger from their government. They're not."

"Senator Paul has a lot of passion," said Sen. Lindsey Graham, R-S.C. "That's a great thing. This is an important issue. ... But to my Republican colleagues, I don't remember any of you coming down here suggesting that President Bush was going to kill anybody with a drone, do you?"

Paul's 13-hour filibuster drew a cadre of Republican senators and one Democrat, Ron Wyden of Oregon, to speak about the constitutionality of allowing lethal drone strikes on U.S. citizens at home and abroad without legal due process. Paul and Republican fundraisers tried to raise money off the publicity powered by the filibuster.

Despite the excitement generated in some conservative circles by Paul, McCain and Graham called it a cynical maneuver.

"I saw colleagues who know better come to the floor and voice some of this same concern, which is totally unfounded," McCain said. "I must say the use of Jane Fonda's name does evoke certain memories with me, and I must say that she is not my favorite American. But I also believe that, as odious as it was, Ms. Fonda acted within her constitutional rights. ...

"To somehow allege or infer that the president of the United States is going to kill somebody like Jane Fonda or somebody who disagrees with the policies is a stretch of imagination, which is, frankly, ridiculous," McCain said.

McCain, a former Navy pilot, was a prisoner of war in North Vietnam in 1972 when Fonda, an Academy Award-winning actress, appeared in Hanoi and criticized U.S. military policies in Vietnam.

Paul, who started speaking about 11:45 a.m. Wednesday, ended his filibuster shortly after midnight Thursday.

While Paul ended his filibuster, Senate Minority Leader Mitch McConnell, also a Kentucky Republican, said he would continue to oppose Brennan's nomination and attempts to end debate on it. McConnell voted against ending debate.

Senate Judiciary Chairman Pat Leahy, D-Vt., announced at a gun hearing Wednesday that the committee was planning a March 20 hearing to examine the domestic use of drones.

Paul, a critic of Obama's unmanned drone policy, started his filibuster by demanding the president or the attorney general issue a statement assuring that unmanned aircraft would not be used in the United States to kill terrorism suspects who are U.S. citizens.

Paul said his focus was on constitutional issues. "We really just want (Obama) to say he won't" attack non-combatants on U.S. soil.

During his filibuster, which repeatedly mentioned the chaos of post-World War I Germany and the rise of Adolf Hitler, Paul said earlier Justice Department letters raised the possibility that the president could target citizens who merely disagreed with him.

Although Paul's filibuster gathered favorable attention throughout the day and into the night Wednesday, not all conservatives were impressed. The conservative editorial page of The Wall Street Journal said: "The country needs more senators who care about liberty, but if Mr. Paul wants to be taken seriously he needs to do more than pull political stunts that fire up impressionable libertarian kids in their college dorms. He needs to know what he's talking about."

Brennan has been closely linked to the drone program. The administration has used the unmanned aircraft to regularly target terror suspects in the Middle East and Africa.

In 2011, U.S.-born cleric Anwar al-Awlaki was killed by a drone strike in Yemen, raising questions about the use of the armed drones on American citizens.